I believe JB weld holds better on metal than plastic. There are many great products out there just have to use the one right for the item you are patching. I might try a cyanoacrylate glue or "crazy glue" as it is usually called, I have used Gorilla Glue version of that to great success on many plastics even saved me $150 on a washing machine control panel replacement when a plastic pin for the knob broke and can only be bought with the whole panel, has held almost 5 years now.
The regular brown foaming Gorilla Glue is better on porous stuff, wood, brick, cloth.